1. Field of the Invention
The present invention relates to metal working and more particularly to a method for assembling that includes disassembling by destroying a temporary connector to create a hole for a permanent separate fastener for temporarily fastening two adjacent workpieces.
2. Description of Related Art
The fuselage of an airplane is constructed from a number of individual panels that are fastened to a frame by a plurality of rivets. Temporary fasteners are typically installed into adjacent parts to insure that the workpieces do not become separated during the installation of the permanent rivets. The temporary fasteners are eventually removed and replaced with a permanent rivet.
Some areas of the aircraft are not fully accessible, thereby requiring the use of a blind rivet which can be installed from only one side of a workpiece. Temporary blind fasteners typically contain a shank which extends through a hole drilled through the workpieces. The shank has a head which prevents the fastener from falling into the xe2x80x9cblindxe2x80x9d side of the assembly. The fastener also contains a pull stem which has a stem head located at the blind end of the shank. The stem head is pulled through the shank to expand the shank and secure the fastener to the workpieces. The temporary fastener is eventually removed by drilling through the head and the shank with a drill of the proper diameter for the shank of the permanent rivet to be installed.
It has been found that drilling temporary blind fasteners of the prior art may create splinters and portions of the head that can scratch the surface of the outer workpiece. Additionally, although the head and enlarged shank end prevent the fastener from falling out of the hole, it has been found that the shank may rotate with the drill bit before the head is totally drilled out, preventing further penetration of the drill. Also the rotation of the shank and head remnants spins the splinters and drill chips to further scratch the surface of the workpiece. It would therefore be desirable to provide a temporary fastener that is easy to remove and does not create scratches on the workpiece surfaces.
A method for creating a permanent hole for a permanent fastener that fastens a first workpiece to an adjacent second workpiece. The method includes: providing a tacking fastener that includes a shank that has an inner channel, a first end, a second end, and a shank, head, the shank head extending from the first end; drilling a tacking hole through the first and second workpieces; inserting the shank into the tacking hole so that the second end extends from the second workpiece and the shank head is adjacent to the first workpiece; expanding the shank to secure the shank to the first and second workpieces; and, drilling the shank head, the shank, the first workpiece, and second workpiece using a drill bit that has a diameter larger than a diameter of the shank head. 
The present invention is a method for creating a hole for a permanent fastener that replaces a temporary fastener for fastening two or more adjacent workpieces. The temporary fastener includes a shank that extends through a hole of the workpieces. Extending from one end of the shank is a conical shaped head. The temporary fastener has an inner channel that extends through the shank from the head to the opposite end. The fastener also contains a pull stem which has a head located adjacent to the blind end of the shank. The stem head is pulled through the shank to expand and is expanded to tightly fasten the shank to the workpieces. The fastener is removed by drilling through the head and the shank.
The diameter of the conical shank head is smaller than the diameter of the drill so that part of the head does not become attached to the drill bit and scratch the workpiece. The conical shape of the head also reduces the volume of fastener material to further reduce the size and amount of chips produced during the drilling process. The tightly engaged shank prevents the fastener from rotating during the drilling operation.